A transmitter is provided having transmission methods that minimize the power needed to ensure reliable reception in a coverage area. In one aspect, data that requires re-transmission as acknowledged mode data is re-transmitted when the power level of the transmission link is higher than a pre-determined level set for reliable reception. The data rate of the re-transmitted data is set according to the difference in the actual power and the pre-determined level. In a second aspect, two transmitting antennae are used to transmit the same signals with a frequency off-set. The frequency off-set can be used to determine the phase of the signals being received at the receiver, so that a phase off-set can be introduced to optimise the effect of interference at the receiver.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A transmitter comprising: a memory for storing a first data that is to be transmitted, and a second data that has been transmitted; a processor for receiving requests to re-transmit the second data from the memory; a monitor for receiving, from user equipment, power control commands indicating a change in power to maintain, at a predetermined level, a power of a transmission link between the transmitter and a receiver associated with the user equipment and for separately summing a number of power control commands indicating that an increase in power is necessary and a number of power control commands indicating that a reduction in power is necessary over a predetermined period of time; a power control unit electrically connected to the monitor, and configured to: control the power of the transmission link such that the power is temporarily higher than the pre-determined level; and maintain the power of the transmission link at a previous level after receiving a power control command from the user equipment that requests a reduction in power; and a data control unit configured to schedule the second data for re-transmission in periods when the power of the transmission link is higher than the pre-determined level based at least in part on a difference in sums.
A transmitter re-transmits data based on power control commands from user equipment. It stores initial and re-transmitted data. It receives power control commands (increase/decrease power) from user equipment to maintain a target signal strength. It separately counts "increase power" and "decrease power" commands over a set time. When the summed "increase power" commands are significantly higher (based on the difference in sums), the transmitter temporarily boosts its transmission power above the target level, then re-sends the data. If a "decrease power" command is received, the transmitter maintains the previous power level. The re-transmission scheduling happens only when power is higher than normal.
2. A transmitter according to claim 1 , wherein the data control unit is configured to control a data rate of the second data when the second data is re-transmitted based on a difference between the power level of the transmission link and the pre-determined level.
The transmitter from the previous description dynamically adjusts the data rate of re-transmitted data. When re-transmitting, the data rate is calculated based on the difference between the actual transmission power level and the pre-determined target power level requested by the user equipment. A larger power difference leads to a higher data rate for the re-transmission.
3. A transmitter according to claim 1 , wherein the data control unit is configured to control a data rate based on an amount of data that requires re-transmission.
The transmitter from the initial description adjusts the data rate of re-transmitted data based on the amount of data that needs to be re-transmitted. A larger amount of data requiring re-transmission will result in a different data rate being selected than if only a small amount of data needed to be re-transmitted.
4. A transmitter according to claim 1 , wherein the data control unit is configured to receive signal quality measurements of the transmission link between the transmitter to the receiver, and to schedule the second data for re-transmission based on an estimation of a channel state.
This invention relates to wireless communication systems, specifically improving data transmission reliability in fading or interference-prone channels. The transmitter includes a data control unit that manages data transmission and retransmission to a receiver. The data control unit receives signal quality measurements from the transmission link, which indicate the current channel conditions between the transmitter and receiver. Using these measurements, the unit estimates the channel state, which reflects the link's reliability for data transmission. Based on this estimation, the data control unit schedules retransmission of data that may have been corrupted or lost due to poor channel conditions. This adaptive retransmission mechanism enhances data integrity and throughput by dynamically adjusting to varying channel states. The system is particularly useful in environments with fluctuating signal quality, such as mobile or high-interference scenarios. The transmitter may also include a data processing unit that encodes and modulates data for transmission, and a transmission unit that sends the processed data to the receiver. The data control unit coordinates these components to ensure efficient and reliable data delivery.
5. A transmitter according to claim 1 , wherein the power control unit is configured to transmit only the first data in periods wherein the power level of the transmission link is equal to the pre-determined level.
The transmitter from the initial description transmits only new data when the power level of the transmission link matches the pre-determined target level requested by the user equipment. Re-transmissions are suppressed when the power level is considered normal and maintained at the set level. This optimizes for throughput when the link quality is stable.
6. A transmitter according to claim 1 , wherein the power control unit is configured to increase the power of the transmission link when a power control command is received that instructs the power control unit to increase the power of the transmission link, but to maintain the power of the link at the previous level when a power control command is received indicating that a reduction in power is necessary.
The transmitter from the initial description responds asymmetrically to power control commands from user equipment. It increases its transmission power when it receives a command to increase power, but it does *not* decrease its transmission power immediately when it receives a command to reduce power. Instead, it maintains the current (previous) power level. This prevents power oscillations.
7. A transmitter according to claim 1 , wherein the data control unit is configured to determine a data rate for the second data depending on the magnitude of the sum.
The transmitter from the initial description calculates the data rate for re-transmitted data based on how much higher the summed "increase power" commands are than the summed "decrease power" commands over a predetermined period of time. If the magnitude of the sum (difference) is large, a higher data rate is used; if the magnitude is small, a lower data rate is used.
8. A transmitter according to claim 1 , wherein the predetermined period of time is a multiple of a transmission time interval (TTI) for the transmission link.
In the transmitter from the initial description, the period over which power control commands are summed (to decide whether to temporarily boost power for re-transmission) is a multiple of the Transmission Time Interval (TTI). This means the period is synchronized with the timing of data transmissions.
9. A transmitter according to claim 8 , wherein the predetermined period is approximately 10 ms.
The transmitter described previously uses a predetermined period of approximately 10 milliseconds to sum the power control commands. This 10ms period is used to calculate the difference between the number of "increase power" commands versus "decrease power" commands to help determine if a power boost for re-transmission is necessary.
10. A transmitter according to claim 1 , further comprising a housing accommodating a Physical Layer, a Medium Access Control Layer, and a Radio Link Layer according to an Open Systems Interface transmission model.
The transmitter described initially is implemented within a housing that contains the Physical Layer, Medium Access Control Layer, and Radio Link Layer, following the Open Systems Interface (OSI) model. This indicates the hardware and software components required to implement the described functionalities in a standardized communication architecture.
11. A transmitter according to claim 10 , wherein the memory comprises a buffer provided in the Radio Link Layer; the power control unit is provided in the Physical Layer, and the data control unit is configured to receive an indication of a quantity of second data for re-transmission from the Radio Link Layer, and to indicate to the Medium Access Control Layer what data is to be transmitted.
Within the layered architecture of the transmitter, the Radio Link Layer holds the buffer for storing transmitted data (used for re-transmissions). The Physical Layer handles power control. The Radio Link Layer signals the quantity of data that needs to be re-transmitted. The data control unit informs the Medium Access Control Layer about which data should be transmitted (new or re-transmitted).
12. A transmitter according to claim 11 , wherein the housing also accommodates a Radio Resource Control layer, and the data control unit is configured to receive measurements of signal quality from a Radio Resource Controller.
The transmitter described earlier also includes a Radio Resource Control (RRC) layer. The data control unit receives signal quality measurements from this RRC layer. This provides another input to the data control unit for deciding when and how to re-transmit data.
13. A method of transmitting data from a transmitter to a receiver associated with an user equipment, the method comprising: transmitting a first data from the transmitter to the receiver; storing the first data that has been transmitted as a second data; receiving requests from the receiver to re-transmit the second data; receiving power control commands indicating a change in power to maintain, at a predetermined level, a power of a transmission link between the transmitter and the receiver; separately summing a number of power control commands indicating that an increase in power is necessary and a number of power control commands indicating that a reduction in power is necessary over a predetermined period of time; controlling the power of the transmission link such that the power is temporarily higher than the pre-determined level; and scheduling the second data for re-transmission in periods when the power of the link is higher than the predetermined level based at least in part on a difference in sums; wherein the power of the transmission link is controlled to be maintained at a previous level after receiving a power control command from the user equipment that requests a reduction in power.
A method for transmitting data from a transmitter to a receiver in user equipment involves transmitting initial data, storing that data, and responding to re-transmission requests. The transmitter receives power control commands (increase/decrease power) from the user equipment to maintain a target signal strength. It counts "increase power" and "decrease power" commands separately over a set time. When the summed "increase power" commands are significantly higher, the transmitter temporarily boosts its transmission power above the target level and schedules the re-transmission. If a "decrease power" command is received, the transmission power remains at the previous level. Re-transmission is scheduled for when power is higher than the normal target level.
14. The method of claim 13 , further comprising controlling a data rate of the second data when the second data is re-transmitted based on a difference between the power level of the transmission link and the pre-determined level.
The data transmission method from the previous description adjusts the data rate of the re-transmitted data. When re-transmitting, the data rate is calculated based on the difference between the actual transmission power level and the pre-determined target power level requested by the user equipment. A larger power difference leads to a higher data rate for the re-transmission.
15. The method of claim 13 , further comprising controlling a data rate based on an amount of data that requires re-transmission.
The data transmission method from the initial method adjusts the data rate of re-transmitted data based on the amount of data that needs to be re-transmitted. A larger amount of data requiring re-transmission will result in a different data rate being selected than if only a small amount of data needed to be re-transmitted.
16. The method of claim 13 , further comprising receiving signal quality measurements of the link between the transmitter to the receiver, and re-transmitting the data based on an estimation of a channel state.
The data transmission method from the initial method involves the transmitter receiving signal quality measurements of the link to the receiver. Based on these measurements, the transmitter estimates the channel state (e.g., signal strength, interference). The scheduling of data re-transmissions is based on this estimated channel state; re-transmissions happen when the channel is good, according to the estimate.
17. The method of claim 13 , further comprising transmitting only first data in periods where the power level of the transmission link is equal to the pre-determined level.
The data transmission method from the initial method transmits only new data when the power level of the transmission link matches the pre-determined target level requested by the user equipment. Re-transmissions are suppressed when the power level is considered normal, optimizing for throughput during stable link conditions.
18. The method of claim 13 , further comprising increasing the power of the transmission link when a power control command is received indicating that this is necessary, but maintaining the power of the link at the previous level when a power control command is received indicating that a reduction in power is necessary.
The data transmission method from the initial method increases its transmission power when it receives a command to increase power, but it does *not* immediately decrease its transmission power when it receives a command to reduce power. Instead, it maintains the current (previous) power level.
19. The method of claim 13 , further comprising determining a data rate for the second data depending on a magnitude of the sum.
The data transmission method from the initial method calculates the data rate for re-transmitted data based on how much higher the summed "increase power" commands are than the summed "decrease power" commands over a predetermined period of time. If the magnitude of the sum is large, a higher data rate is used; if the magnitude is small, a lower data rate is used.
20. The method of claim 13 , wherein the predetermined period of time is a multiple of a transmission time interval (TTI) for the transmission link.
In the data transmission method from the initial method, the period over which power control commands are summed (to decide whether to temporarily boost power for re-transmission) is a multiple of the Transmission Time Interval (TTI). This ensures the period is synchronized with the timing of data transmissions.
21. The method of claim 20 , wherein the pre-determined period is approximately 10 ms.
In the data transmission method described previously, a predetermined period of approximately 10 milliseconds is used to sum the power control commands. This 10ms period is used to calculate the difference between the number of "increase power" commands versus "decrease power" commands to help determine if a power boost for re-transmission is necessary.
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August 1, 2005
August 6, 2013
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